Li Jiarui, Zhou Jian, Wang Tao, Chen Xu, Zhang Yaxuan, Wan Qiang, Zhu Jian
State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, and School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China.
Nanoscale. 2020 Apr 30;12(16):8991-8996. doi: 10.1039/d0nr01103g.
Lithium-sulfur (Li-S) batteries are attracting extensive interest owing to their low cost and potential for applications in high-density energy storage systems. However, their widespread application is severely plagued by poor cycling stability, inferior rate capability and low coulombic efficiency, which are largely attributed to the shuttling effect of soluble polysulfides. Herein, we report an architecture of an N,P co-doped biological carbon-based covalent sulfur composite (NP@BCCSC), which acts as a cathode for highly robust Li-S batteries. The NP@BCCSC can not only buffer the volume expansion of sulfur during the charge/discharge process, but also shows strong absorption towards soluble polysulfides, which can effectively suppress the shuttling effect. As a cathode for Li-S batteries, the NP@BCCSC with a sulfur content of 20.1% exhibits a reversible capacity of 1190 mA h g-1 (all specific capacities are calculated based on the mass of sulfur) at a current density of 500 mA g-1 after 500 cycles with an average coulombic efficiency of approximately 100%. Moreover, the NP@BCCSC offers a highly robust cycling stability (an ultralow capacity fading rate of 0.0024% per cycle during 15 000 consecutive cycles) and an excellent rate capability (high specific capacity of 920 mA h g-1 even at a current density of 10 000 mA g-1), indicating its great potential for applications in future energy storage systems.
锂硫（Li-S）电池因其低成本以及在高密度储能系统中的应用潜力而备受广泛关注。然而，其广泛应用受到循环稳定性差、倍率性能不佳和库仑效率低的严重困扰，这些问题很大程度上归因于可溶性多硫化物的穿梭效应。在此，我们报道了一种氮、磷共掺杂的生物碳基共价硫复合材料（NP@BCCSC）的结构，它作为高稳定性锂硫电池的正极。NP@BCCSC不仅可以缓冲充放电过程中硫的体积膨胀，还对可溶性多硫化物表现出强烈的吸附作用，能够有效抑制穿梭效应。作为锂硫电池的正极，硫含量为20.1%的NP@BCCSC在500 mA g-1的电流密度下经过500次循环后，具有1190 mA h g-1的可逆容量（所有比容量均基于硫的质量计算），平均库仑效率约为100%。此外，NP@BCCSC具有高度稳定的循环稳定性（在连续15000次循环中每循环的超低容量衰减率为0.0024%）和优异的倍率性能（即使在10000 mA g-1的电流密度下仍具有920 mA h g-1的高比容量），表明其在未来储能系统中的应用潜力巨大。
